Laboratory Studies

Abuse and dependence

Detection of drugs in sweat and hair is a recent addition to drug abuse detection technology. However, it is not used widely.

Withdrawal

See the list below:

Electrolytes

CBC count

Urine drug screen is rarely useful.

Intoxication

See the list below:

Comprehensive urine drug testing is performed when the drug abuse habit of the patient is unknown but suspected. Some labs use the inexpensive thin-layer chromatography (TLC) procedure. This test has low sensitivity for commonly used drugs. TLC cannot detect fentanyl.

Enzyme immunoassay and radioimmunoassay are more sensitive than TLC, but they are less specific because molecules with similar functional groups cross-react with antibodies. These are relatively inexpensive tests.

Gas-liquid chromatography (GLC) and gas chromatography-mass spectrometry (GC-MS) are very sensitive and specific tests, but they are time consuming, labor intensive, and expensive.

In drug abuse detection, knowing the half-life of the drug, the biotransformation of the drug, and the excretion route of the drug are important.

Screening and confirmation cut-off concentration for heroin, methadone, morphine, and codeine is 300 ng/mL and are detected in urine within 1-4 days.

False-negative results occur more easily than false positives, simply because once a test is screened negative, it is not tested further. The federal government requires that the results of the drug testing programs go directly to medical review offices to prevent improper interpretation of drug testing data.

Blood alcohol levels also may be tested.

Addiction

In case of historical or clinical evidence of IV drug abuse, perform the following:

LFT

Rapid plasma reagent (RPR)

Hepatitis viral testing

HIV testing

Blood cultures (in appropriate clinical setting)

Next:

Imaging Studies

For addiction, in case of historical or clinical evidence of IV drug abuse, perform an x-ray of the lungs (eg, history of injecting drugs contaminated with microcrystalline talc) to search for evidence of pulmonary fibrosis.

Previous

Next:

Other Tests

Naloxone challenge test: This test is performed to assess physical dependence. As an intramuscular injection or IV, 0.2-0.8 mg of naloxone is administered.

A positive test is indicative of physical dependence and consists of typical withdrawal symptoms and signs. These symptoms and signs usually last for 30-60 minutes.

This test is found to be very helpful before starting opiate antagonists for maintenance therapy. Starting opioid antagonists, such as naltrexone, soon after detoxification may cause withdrawal symptoms and discourage patients from further treatment.

[Guideline] American Psychiatric Association. Practice guideline for the treatment of patients with substance use disorders, 2nd edition. In American Psychiatric Association Practice Guidelines for the Treatment of Psychiatric Disorders: Compendium 2006. Arlington, VA: American Psychiatric Association, 2006 (pp. 291–563). Available at http://psychiatryonline.org/content.aspx?bookid=28&sectionid=1675010.

National Institutes of Health (NIH) National Center for Complementary and Integrative Health (NCCIH). In the News: Kratom (Mitragyna speciosa). Available at https://nccih.nih.gov/news/kratom. February 23, 2018; Accessed: March 14, 2018.

Disclosure: Serve(d) as a director, officer, partner, employee, advisor, consultant or trustee for: Doctor On Demand<br/>Received income in an amount equal to or greater than $250 from: Blue Cross Blue Shield Federal Employee Program<br/>Received royalty from Lippincott Williams & Wilkins for book editor; Received grant/research funds from National Alliance for Research in Schizophrenia and Depression for independent contractor; Received consulting fee from Blue Cross Blue Shield Association for consulting. for: Received book royalty from American Psychiatric Publishing Inc.

The authors and editors of Medscape Drugs & Diseases gratefully acknowledge the contributions of previous authors Ziaur Rehman, MD, Suzan Khoromi, MD, James E Douglas, MD, Steven A Adelman, MD, and William J Meehan, MD, PhD to the development and writing of this article.